"Job-Hopping in Silicon Valley: Some Evidence Concerning the Micro-Foundations of a High Technology Cluster"

Observers of Silicon Valley's computer cluster report that employees move rapidly between competing firms, but evidence supporting this claim is scarce. Job-hopping is important in computer clusters because it facilitates the reallocation of talent and resources toward firms with superior innovations. Using new data on labor mobility, we find higher rates of job-hopping for college-educated men in Silicon Valley's computer industry than in computer clusters located out of the state. Mobility rates in other California computer clusters are similar to Silicon Valley's, suggesting some role for features of California law that make non-compete agreements unenforceable. Consistent with our model of innovation, mobility rates outside of computer industries are no higher in California than elsewhere.

Job-Hopping in Silicon Valley: Some Evidence Concerning the Micro-Foundations of a High Technology Cluster

Observers of Silicon Valley’s computer cluster report that employees move rapidly between competing firms, but evidence supporting this claim is scarce. Job-hopping is important in computer clusters because it facilitates the reallocation of talent and resources toward firms with superior innovations. Using new data on labor mobility, we find higher rates of job-hopping for college-educated men in Silicon Valley’s computer industry than in computer clusters located out of the state. Mobility rates in other California computer clusters are similar to Silicon Valley’s, suggesting some role for features of California law that make non-compete agreements unenforceable. Consistent with our model of innovation, mobility rates outside of computer industries are no higher in California than elsewhere.agglomerations, clusters, non-compete agreements, human capital, innovation, Silicon Valley, modular production.

Optimizing Photonic Nanostructures via Multi-fidelity Gaussian Processes

We apply numerical methods in combination with finite-difference-time-domain (FDTD) simulations to optimize transmission properties of plasmonic mirror color filters using a multi-objective figure of merit over a five-dimensional parameter space by utilizing novel multi-fidelity Gaussian processes approach. We compare these results with conventional derivative-free global search algorithms, such as (single-fidelity) Gaussian Processes optimization scheme, and Particle Swarm Optimization---a commonly used method in nanophotonics community, which is implemented in Lumerical commercial photonics software. We demonstrate the performance of various numerical optimization approaches on several pre-collected real-world datasets and show that by properly trading off expensive information sources with cheap simulations, one can more effectively optimize the transmission properties with a fixed budget.Comment: NIPS 2018 Workshop on Machine Learning for Molecules and Materials. arXiv admin note: substantial text overlap with arXiv:1811.0075

Magnetism in one-dimensional metamaterials: Double hyperbolic media and magnetic surface states

Metamaterials with magnetic properties have been widely investigated with rather complex two- and three-dimensional resonant structures. Here we propose conceptually and demonstrate experimentally a mechanism for broadband optical magnetism in simpler one-dimensional systems. We experimentally demonstrate that alternating high-index dielectric/metal multilayer hyperbolic metamaterials can exhibit a strong magnetic response including variously µ>1 to µ<0. By engineering the electric permittivity as well, we reveal an epsilon and mu near zero regime. We show that modifications of internal metamaterial structure can lead to either type I or type II magnetic hyperbolic dispersion, thereby generalizing the notion of a hyperbolic metamaterial to encompass both TE and TM polarizations in simple multilayer geometries. Finally, we show that a negative magnetic response can give rise to TE interface-bound states, analogous to their TM counterparts, surface plasmon polaritons

Behavior studies related to pesticides: Agricultural chemicals and Iowa agricultural-chemical dealers

The agricultural sector of the United States economy has long been recognized for its productive capacity and relative efficiency. This has resulted in abundant, high-quality, and relatively low-cost food and fiber. Many factors have made contributions to this phenomenon: adequate natural resources, research and resulting technology, the ready availability of this technology to farmers, available capital and labor, and the entrepreneurial ability of the American farmer to combine these resources efficiently. One type of research and technology that has made a major contribution to the productive capacity and efficiency is that which relates to agricultural chemicals — pesticides for the control of insects, weeds, and diseases. The positive contribution of agricultural chemicals is generally accepted and can be validated. However, there is an expressed concern regarding the possible consequences of improper use of agricultural chemicals that might result in danger to the user, crops, livestock, aquatic and wildlife, and to the ultimate consumer of food products. In its extreme form this concern is expressed in terms of strict control or the abolition of the use of agricultural chemicals. Other proposals call for much stricter control over the clearance, sale, and use of chemicals

Релятивистское приближение для определения положений минимумов дифференциальных сечений и точек полной спиновой поляризации процесса упругого рассеяния электронов на тяжелых атомах

Пропонується метод оптичного потенціалу для описання процесу потенціального пружного розсіювання електронів багатоелектронними атомами з релятивістською поправкою до обмінної взаємодії. Ця поправка також використовується при самоузгоджених розрахунках атомних характеристик та величини дипольної статичної поляризовності атома-мішені. Підхід базується на наближенні локальної густини теорії функціонала густини та застосовується для розрахунку енергій та кутів особливостей у диференціальних перерізах і функціях спінової поляризації — відповідно критичних мінімумів та точок повної (100%) поляризації — при розсіюванні електронів на атомах ртуті в широкій, 10–1500 еВ, області енергій зіткнень.The optical potential approach has been suggested to describe the process of potential elastic electron scattering by a multielectron atom with the relativistic correction to the exchange interaction. This correction is also used for the self-consistent calculation of atomic characteristics and the target atom dipole static polarizability. The above approach is based on the local density approximation of the density functional theory. It is applied to calculate the energies and angles of the features in the differential cross sections and spin polarization functions, i.e. the critical minima and the points of total (100%) polarization of the electron scattering by Hg atoms in the wide (10–1500 eV) impact energy range